PhD Chapter 1
Global - Analyses and regressions
This series of files compile analyses done for the global analysis of Chapter 1 (version of May 15th).
All analyses have been done with PRIMER-e 6 and R 4.1.0.
Click on the table of contents in the left margin to assess a specific analysis.
Click on a figure to zoom it
We used data from subtidal ecosystems (see metadata files for more information). Only stations that have been sampled both for abiotic parameters and benthic species were included.
Selected variables for the analyses:
- Bathymetry: depth
- Percentage of organic matter: om
- Percentage of gravel: gravel
- Percentage of sand: sand
- Percentage of silt: silt
- Percentage of clay: clay
- Concentration of arsenic: arsenic
- Concentration of cadmium: cadmium
- Concentration of chromium: chromium
- Concentration of copper: copper
- Concentration of iron: iron
- Concentration of manganese: manganese
- Concentration of mercury: mercury
- Concentration of lead: lead
- Concentration of zinc: zinc
- Specific richness: S
- Total density of individuals: N
- Shannon’s diversity: H
- Piélou’s evenness: J
1. Cluster characteristics
This section present each clusters, with (i) the average values for habitat and metal variables, (ii) the average values for diversity indices and (iii) the characteristic taxa obtained by SIMPER and IndVal analyses. Taxon densities were (log+1) transformed.
0.5 mm community
Habitat and metals
| Mean | SD | SE | Median | Min | Max | 95% CI | |
|---|---|---|---|---|---|---|---|
| depth | 6.994 | 1.403 | 0.351 | 7.100 | 4.500 | 8.900 | 0.687 |
| om | 2.584 | 1.660 | 0.415 | 2.378 | 1.108 | 8.260 | 0.813 |
| gravel | 0.000 | 0.000 | 0.000 | 0.000 | 0.000 | 0.000 | 0.000 |
| sand | 0.000 | 0.000 | 0.000 | 0.000 | 0.000 | 0.000 | 0.000 |
| silt | 0.001 | 0.000 | 0.000 | 0.001 | 0.001 | 0.001 | 0.000 |
| clay | 0.999 | 0.000 | 0.000 | 0.999 | 0.999 | 0.999 | 0.000 |
| arsenic | 3.744 | 1.293 | 0.323 | 3.750 | 1.50 | 6.00 | 0.633 |
| cadmium | 0.146 | 0.027 | 0.007 | 0.140 | 0.09 | 0.19 | 0.013 |
| chromium | 80.287 | 22.934 | 5.734 | 79.450 | 45.80 | 143.30 | 11.238 |
| copper | 19.887 | 5.319 | 1.330 | 19.600 | 11.20 | 32.40 | 2.606 |
| iron | 64730.012 | 14916.663 | 3729.166 | 64356.210 | 32899.91 | 98544.60 | 7309.030 |
| manganese | 2173.444 | 1284.808 | 321.202 | 2048.495 | 705.69 | 5962.19 | 629.544 |
| mercury | 0.036 | 0.063 | 0.016 | 0.020 | 0.00 | 0.25 | 0.031 |
| lead | 7.316 | 2.312 | 0.578 | 7.115 | 3.59 | 12.18 | 1.133 |
| zinc | 77.213 | 16.879 | 4.220 | 74.900 | 47.10 | 101.50 | 8.270 |
| Mean | SD | SE | Median | Min | Max | 95% CI | |
|---|---|---|---|---|---|---|---|
| depth | 13.720 | 12.804 | 1.639 | 8.800 | 1.600 | 60.600 | 3.213 |
| om | 0.524 | 0.337 | 0.043 | 0.409 | 0.186 | 1.528 | 0.084 |
| gravel | 0.059 | 0.142 | 0.018 | 0.000 | 0.000 | 0.701 | 0.036 |
| sand | 0.533 | 0.415 | 0.053 | 0.675 | 0.000 | 1.000 | 0.104 |
| silt | 0.113 | 0.187 | 0.024 | 0.032 | 0.000 | 0.869 | 0.047 |
| clay | 0.295 | 0.441 | 0.056 | 0.000 | 0.000 | 1.000 | 0.111 |
| arsenic | 2.506 | 1.282 | 0.187 | 2.2 | 1.10 | 7.600 | 0.367 |
| cadmium | 0.110 | 0.041 | 0.006 | 0.1 | 0.03 | 0.220 | 0.012 |
| chromium | 54.502 | 25.249 | 3.683 | 47.4 | 10.90 | 125.000 | 7.218 |
| copper | 6.857 | 5.021 | 0.732 | 5.0 | 2.20 | 22.100 | 1.435 |
| iron | 57555.237 | 30299.094 | 4419.577 | 49344.4 | 14089.92 | 188857.220 | 8662.212 |
| manganese | 930.994 | 424.869 | 61.974 | 833.6 | 251.67 | 2298.700 | 121.466 |
| mercury | 0.007 | 0.010 | 0.001 | 0.0 | 0.00 | 0.036 | 0.003 |
| lead | 3.259 | 1.813 | 0.265 | 2.6 | 1.02 | 9.500 | 0.518 |
| zinc | 43.540 | 15.429 | 2.251 | 41.7 | 15.90 | 101.400 | 4.411 |
| Mean | SD | SE | Median | Min | Max | 95% CI | |
|---|---|---|---|---|---|---|---|
| depth | 32.756 | 19.095 | 2.024 | 29.500 | 2.100 | 77.000 | 3.967 |
| om | 1.762 | 0.965 | 0.102 | 1.525 | 0.392 | 4.415 | 0.201 |
| gravel | 0.017 | 0.097 | 0.010 | 0.000 | 0.000 | 0.765 | 0.020 |
| sand | 0.463 | 0.220 | 0.023 | 0.512 | 0.000 | 0.868 | 0.046 |
| silt | 0.491 | 0.209 | 0.022 | 0.480 | 0.021 | 0.845 | 0.043 |
| clay | 0.030 | 0.148 | 0.016 | 0.000 | 0.000 | 0.979 | 0.031 |
| arsenic | 3.886 | 2.276 | 0.243 | 3.050 | 1.80 | 16.000 | 0.475 |
| cadmium | 0.137 | 0.031 | 0.003 | 0.140 | 0.06 | 0.230 | 0.007 |
| chromium | 58.073 | 16.012 | 1.707 | 58.600 | 31.10 | 110.700 | 3.345 |
| copper | 12.334 | 4.772 | 0.509 | 13.100 | 3.60 | 28.700 | 0.997 |
| iron | 55265.811 | 15722.531 | 1676.027 | 55752.250 | 28355.90 | 151226.400 | 3284.953 |
| manganese | 1180.457 | 582.751 | 62.122 | 1020.300 | 423.10 | 3435.200 | 121.756 |
| mercury | 0.024 | 0.016 | 0.002 | 0.021 | 0.00 | 0.087 | 0.003 |
| lead | 5.455 | 1.888 | 0.201 | 5.400 | 1.70 | 12.100 | 0.394 |
| zinc | 61.091 | 16.640 | 1.774 | 62.950 | 27.60 | 141.000 | 3.477 |
Diversity
| Mean | SD | SE | Median | Min | Max | 95% CI | |
|---|---|---|---|---|---|---|---|
| S | 27.812 | 3.781 | 0.945 | 28.500 | 21.000 | 34.000 | 1.853 |
| N | 1411.188 | 410.971 | 102.743 | 1433.000 | 636.000 | 2103.000 | 201.372 |
| H | 1.823 | 0.268 | 0.067 | 1.882 | 1.246 | 2.247 | 0.131 |
| J | 0.550 | 0.081 | 0.020 | 0.559 | 0.409 | 0.682 | 0.040 |
| delta | 38.494 | 6.594 | 1.648 | 39.262 | 25.409 | 49.097 | 3.231 |
| delta_plus | 63.663 | 1.847 | 0.462 | 63.735 | 58.995 | 67.300 | 0.905 |
| delta_star | 51.896 | 4.667 | 1.167 | 52.793 | 44.058 | 59.625 | 2.287 |
| Mean | SD | SE | Median | Min | Max | 95% CI | |
|---|---|---|---|---|---|---|---|
| S | 12.197 | 6.077 | 0.778 | 12.000 | 1 | 35.000 | 1.525 |
| N | 110.131 | 175.663 | 22.491 | 56.000 | 1 | 941.000 | 44.082 |
| H | 1.619 | 0.612 | 0.078 | 1.623 | 0 | 2.737 | 0.154 |
| J | 0.683 | 0.213 | 0.027 | 0.706 | 0 | 1.000 | 0.053 |
| delta | 50.139 | 16.129 | 2.065 | 53.777 | 0 | 77.778 | 4.048 |
| delta_plus | 68.787 | 9.821 | 1.257 | 70.351 | 0 | 77.778 | 2.465 |
| delta_star | 70.279 | 10.910 | 1.397 | 72.837 | 0 | 79.812 | 2.738 |
| Mean | SD | SE | Median | Min | Max | 95% CI | |
|---|---|---|---|---|---|---|---|
| S | 13.270 | 4.871 | 0.516 | 13.000 | 4.000 | 24.000 | 1.012 |
| N | 92.180 | 71.364 | 7.565 | 75.000 | 4.000 | 450.000 | 14.826 |
| H | 1.896 | 0.430 | 0.046 | 1.971 | 0.975 | 2.577 | 0.089 |
| J | 0.758 | 0.129 | 0.014 | 0.781 | 0.402 | 1.000 | 0.027 |
| delta | 55.694 | 9.436 | 1.000 | 58.642 | 28.289 | 75.926 | 1.960 |
| delta_plus | 70.368 | 1.994 | 0.211 | 70.370 | 63.333 | 75.926 | 0.414 |
| delta_star | 71.045 | 3.169 | 0.336 | 71.358 | 59.142 | 79.779 | 0.658 |
Here are the graphs plotting specific richness and taxonomic distinctness:
As a measure of \(\beta\) diversity, mean Bray-Curtis dissimilarity is:
- 0.38 within cluster 1
- 0.85 within cluster 2
- 0.69 within cluster 3
Characteristic taxa
## cluster indicator_value probability
## capitella_sp 1 0.9861 0.001
## nephtys_sp 1 0.9861 0.001
## prionospio_steenstrupi 1 0.9692 0.001
## phyllodoce_groenlandica 1 0.9664 0.001
## cirratulidae_spp 1 0.9331 0.001
## phoronida 1 0.9288 0.001
## scoloplos_armiger 1 0.8889 0.001
## sarsicytheridea_sp 1 0.8706 0.001
## polychaeta 1 0.8100 0.001
## limecola_balthica 1 0.7949 0.001
## sertulariidae_spp 1 0.7531 0.001
## eteone_sp 1 0.7064 0.001
## bipalponephtys_neotena 1 0.6982 0.001
## campanulariidae_spp 1 0.6946 0.001
## harpacticoida 1 0.5711 0.001
## euchone_analis 1 0.5625 0.001
## pholoe_longa 1 0.5096 0.001
## podocopida 1 0.4323 0.001
## glycera_dibranchiata 1 0.4297 0.001
## hediste_diversicolor 1 0.4257 0.001
## tharyx_sp 1 0.3750 0.001
## diastylis_sculpta 1 0.3651 0.001
## phoxocephalus_holbolli 1 0.3346 0.003
## pholoe_minuta_tecta 1 0.3282 0.001
## praxillella_praetermissa 1 0.3099 0.001
## microphthalmus_sczelkowii 1 0.3009 0.001
## aricidea_sp 1 0.2998 0.001
## sabellidae_spp 1 0.2959 0.002
## solenoidea 1 0.2878 0.001
## microphthalmus_sp 1 0.2500 0.001
## pontoporeia_femorata 1 0.2477 0.023
## axinopsida_orbiculata 1 0.2457 0.006
## eucratea_loricata 1 0.2286 0.002
## bivalvia 1 0.2090 0.004
## cylichna_alba 1 0.1875 0.002
## harmothoe_imbricata 1 0.1875 0.001
## eudendriidae_spp 1 0.1724 0.003
## gammaridea 1 0.1680 0.003
## hemicythere_villosa 1 0.1624 0.002
## spio_filicornis 1 0.1403 0.013
## eteone_longa 1 0.1250 0.009
## hartmania_moorei 1 0.1250 0.008
## macoma_sp 1 0.1250 0.007
## monticellina_sp 1 0.1250 0.009
## pherusa_sp 1 0.1250 0.014
## scoletoma_tetraura 1 0.1250 0.014
## capitellidae_spp 1 0.1193 0.013
## brachyura 1 0.1183 0.005
## serripes_groenlandicus 1 0.0509 0.045
## echinarachnius_parma 2 0.5050 0.001
## nematoda 2 0.3257 0.007
## spisula_solidissima 2 0.2951 0.002
## crenella_decussata 2 0.2317 0.006
## annelida 2 0.2131 0.005
## polygordius_sp 2 0.1894 0.019
## nephtys_caeca 2 0.1754 0.024
## orchomenella_minuta 2 0.1003 0.044
## halacaridae_spp 2 0.0984 0.042
## ophiura_robusta 2 0.0984 0.027
## lepeta_caeca 2 0.0912 0.031
## hiatella_arctica 2 0.0899 0.050
## macoma_calcarea 3 0.6715 0.001
## eudorellopsis_integra 3 0.6687 0.001
## ennucula_tenuis 3 0.4903 0.001
## leucon_leucon_nasicoides 3 0.4655 0.001
## goniada_maculata 3 0.4399 0.001
## protomedeia_grandimana 3 0.3599 0.003
## ostracoda 3 0.3403 0.005
## nephtys_incisa 3 0.3293 0.002
## thyasira_gouldi 3 0.3186 0.002
## akanthophoreus_gracilis 3 0.3118 0.003
## amphipoda 3 0.2632 0.027
## quasimelita_formosa 3 0.2374 0.009
## aceroides_aceroides_latipes 3 0.2267 0.010
## chaetodermatida 3 0.1566 0.025
## sipuncula 3 0.1410 0.047
##
## Sum of probabilities = 81.499
##
## Sum of Indicator Values = 35.53
##
## Sum of Significant Indicator Values = 28.89
##
## Number of Significant Indicators = 76
##
## Significant Indicator Distribution
##
## 1 2 3
## 49 12 15
| phylum | cl1 | cl2 | cl3 |
|---|---|---|---|
| Annelida | 20206 | 1497 | 3099 |
| Phoronida | 1137 | 3 | 0 |
| Arthropoda | 861 | 2199 | 3472 |
| Mollusca | 327 | 1404 | 1168 |
| Cnidaria | 36 | 50 | 0 |
| Bryozoa | 6 | 24 | 0 |
| Echinodermata | 4 | 538 | 37 |
| Hemichordata | 2 | 0 | 0 |
| Chaetognatha | 0 | 1 | 0 |
| Nematoda | 0 | 982 | 395 |
| Nemertea | 0 | 17 | 4 |
| Sipuncula | 0 | 3 | 29 |
| average | sd | ratio | ava | avb | cumsum | |
|---|---|---|---|---|---|---|
| bipalponephtys_neotena | 0.0735 | 0.0147 | 4.99 | 6.17 | 0.278 | 0.0794 |
| nephtys_sp | 0.0726 | 0.0124 | 5.85 | 5.92 | 0.0682 | 0.158 |
| prionospio_steenstrupi | 0.0494 | 0.0129 | 3.84 | 4.09 | 0.13 | 0.211 |
| phoronida | 0.0439 | 0.0162 | 2.71 | 3.64 | 0.0341 | 0.259 |
| scoloplos_armiger | 0.0437 | 0.0189 | 2.32 | 3.7 | 0.202 | 0.306 |
| capitella_sp | 0.0392 | 0.0111 | 3.53 | 3.23 | 0.0455 | 0.348 |
| phyllodoce_groenlandica | 0.0382 | 0.0101 | 3.8 | 3.23 | 0.113 | 0.39 |
| cirratulidae_spp | 0.0298 | 0.0122 | 2.45 | 2.42 | 0.0114 | 0.422 |
| sarsicytheridea_sp | 0.027 | 0.0139 | 1.95 | 2.26 | 0.0114 | 0.451 |
| limecola_balthica | 0.0251 | 0.0154 | 1.63 | 2.05 | 0.0455 | 0.478 |
| harpacticoida | 0.0211 | 0.0129 | 1.63 | 2.21 | 0.902 | 0.501 |
| eteone_sp | 0.0192 | 0.0129 | 1.49 | 1.62 | 0.0768 | 0.522 |
| phoxocephalus_holbolli | 0.0169 | 0.0133 | 1.27 | 1.36 | 1.02 | 0.54 |
| euchone_analis | 0.0164 | 0.017 | 0.964 | 1.43 | 0 | 0.558 |
| nematoda | 0.0151 | 0.02 | 0.756 | 0 | 1.21 | 0.574 |
| pholoe_sp | 0.0149 | 0.0145 | 1.03 | 1.19 | 0.258 | 0.59 |
| pholoe_longa | 0.0145 | 0.0141 | 1.03 | 1.21 | 0.0965 | 0.606 |
| echinarachnius_parma | 0.0134 | 0.0139 | 0.966 | 0 | 1.1 | 0.62 |
| pholoe_minuta_tecta | 0.0123 | 0.0162 | 0.757 | 0.959 | 0.137 | 0.633 |
| podocopida | 0.0112 | 0.0154 | 0.727 | 0.944 | 0.0114 | 0.646 |
| sabellidae_spp | 0.0108 | 0.0152 | 0.708 | 0.909 | 0.0114 | 0.657 |
| pontoporeia_femorata | 0.0104 | 0.013 | 0.8 | 0.804 | 0.0114 | 0.668 |
| hediste_diversicolor | 0.0102 | 0.00999 | 1.02 | 0.842 | 0.102 | 0.679 |
| microphthalmus_sczelkowii | 0.0094 | 0.0143 | 0.657 | 0.761 | 0.0294 | 0.69 |
| diastylis_sculpta | 0.00927 | 0.0122 | 0.758 | 0.783 | 0.0114 | 0.7 |
| average | sd | ratio | ava | avb | cumsum | |
|---|---|---|---|---|---|---|
| nephtys_sp | 0.07 | 0.0112 | 6.23 | 5.92 | 0.0156 | 0.0774 |
| prionospio_steenstrupi | 0.0487 | 0.0107 | 4.56 | 4.09 | 0 | 0.131 |
| bipalponephtys_neotena | 0.0457 | 0.0192 | 2.38 | 6.17 | 2.39 | 0.182 |
| scoloplos_armiger | 0.0438 | 0.0176 | 2.49 | 3.7 | 0 | 0.23 |
| phoronida | 0.0423 | 0.0155 | 2.73 | 3.64 | 0 | 0.277 |
| capitella_sp | 0.0379 | 0.0102 | 3.73 | 3.23 | 0 | 0.319 |
| phyllodoce_groenlandica | 0.0379 | 0.0086 | 4.4 | 3.23 | 0 | 0.361 |
| cirratulidae_spp | 0.0286 | 0.0116 | 2.47 | 2.42 | 0 | 0.393 |
| sarsicytheridea_sp | 0.026 | 0.0133 | 1.95 | 2.26 | 0 | 0.421 |
| limecola_balthica | 0.0244 | 0.0149 | 1.64 | 2.05 | 0 | 0.448 |
| harpacticoida | 0.0215 | 0.012 | 1.78 | 2.21 | 0.519 | 0.472 |
| eudorellopsis_integra | 0.0191 | 0.0161 | 1.18 | 0.0687 | 1.68 | 0.493 |
| eteone_sp | 0.0187 | 0.0124 | 1.5 | 1.62 | 0.0234 | 0.514 |
| macoma_calcarea | 0.0158 | 0.0112 | 1.41 | 0.0687 | 1.4 | 0.531 |
| euchone_analis | 0.0157 | 0.0163 | 0.964 | 1.43 | 0 | 0.549 |
| phoxocephalus_holbolli | 0.0153 | 0.0128 | 1.19 | 1.36 | 0.156 | 0.566 |
| pholoe_sp | 0.0143 | 0.0118 | 1.21 | 1.19 | 0.702 | 0.582 |
| pholoe_longa | 0.014 | 0.0138 | 1.01 | 1.21 | 0.0297 | 0.597 |
| pontoporeia_femorata | 0.0124 | 0.0129 | 0.965 | 0.804 | 0.605 | 0.611 |
| sabellidae_spp | 0.0114 | 0.0149 | 0.768 | 0.909 | 0.232 | 0.623 |
| pholoe_minuta_tecta | 0.0112 | 0.0156 | 0.716 | 0.959 | 0 | 0.636 |
| podocopida | 0.0107 | 0.0147 | 0.724 | 0.944 | 0 | 0.648 |
| hediste_diversicolor | 0.00966 | 0.00911 | 1.06 | 0.842 | 0.169 | 0.658 |
| leucon_leucon_nasicoides | 0.00947 | 0.0124 | 0.765 | 0 | 0.828 | 0.669 |
| diastylis_sculpta | 0.00943 | 0.0117 | 0.806 | 0.783 | 0.144 | 0.679 |
| protomedeia_grandimana | 0.0092 | 0.011 | 0.836 | 0 | 0.803 | 0.689 |
| axinopsida_orbiculata | 0.00915 | 0.011 | 0.831 | 0.677 | 0.322 | 0.7 |
| average | sd | ratio | ava | avb | cumsum | |
|---|---|---|---|---|---|---|
| bipalponephtys_neotena | 0.065 | 0.0407 | 1.6 | 0.278 | 2.39 | 0.0709 |
| eudorellopsis_integra | 0.0484 | 0.0439 | 1.1 | 0.0294 | 1.68 | 0.124 |
| nematoda | 0.0427 | 0.0502 | 0.85 | 1.21 | 0.676 | 0.17 |
| macoma_calcarea | 0.0396 | 0.0335 | 1.18 | 0.289 | 1.4 | 0.213 |
| echinarachnius_parma | 0.0331 | 0.0368 | 0.901 | 1.1 | 0.15 | 0.25 |
| phoxocephalus_holbolli | 0.0289 | 0.034 | 0.85 | 1.02 | 0.156 | 0.281 |
| harpacticoida | 0.0277 | 0.0291 | 0.952 | 0.902 | 0.519 | 0.311 |
| protomedeia_grandimana | 0.0265 | 0.0344 | 0.768 | 0.225 | 0.803 | 0.34 |
| leucon_leucon_nasicoides | 0.0232 | 0.0308 | 0.753 | 0.0114 | 0.828 | 0.365 |
| ennucula_tenuis | 0.0216 | 0.0246 | 0.877 | 0.0774 | 0.774 | 0.389 |
| pholoe_sp | 0.0211 | 0.0228 | 0.926 | 0.258 | 0.702 | 0.412 |
| spisula_solidissima | 0.0209 | 0.0386 | 0.542 | 0.753 | 0 | 0.435 |
| pontoporeia_femorata | 0.0186 | 0.0339 | 0.549 | 0.0114 | 0.605 | 0.455 |
| amphipoda | 0.0156 | 0.021 | 0.741 | 0.185 | 0.452 | 0.472 |
| goniada_maculata | 0.0149 | 0.0202 | 0.736 | 0.0114 | 0.523 | 0.488 |
| maldanidae_spp | 0.0148 | 0.0282 | 0.523 | 0.0114 | 0.529 | 0.504 |
| ostracoda | 0.0138 | 0.0208 | 0.664 | 0.0455 | 0.507 | 0.52 |
| thyasira_gouldi | 0.0134 | 0.0224 | 0.599 | 0.0114 | 0.498 | 0.534 |
| akanthophoreus_gracilis | 0.0131 | 0.0212 | 0.619 | 0.0227 | 0.506 | 0.548 |
| nephtys_incisa | 0.0109 | 0.0164 | 0.668 | 0.0341 | 0.371 | 0.56 |
| oligochaeta | 0.0107 | 0.0258 | 0.415 | 0.166 | 0.266 | 0.572 |
| polynoidae_spp | 0.0106 | 0.0181 | 0.584 | 0.0638 | 0.341 | 0.584 |
| axinopsida_orbiculata | 0.0103 | 0.0222 | 0.462 | 0.0341 | 0.322 | 0.595 |
| crenella_decussata | 0.00963 | 0.02 | 0.482 | 0.328 | 0.0201 | 0.605 |
| mytilus_sp | 0.00954 | 0.0219 | 0.436 | 0.341 | 0.0824 | 0.616 |
| thracia_septentrionalis | 0.0094 | 0.0201 | 0.467 | 0.19 | 0.183 | 0.626 |
| caprella_septentrionalis | 0.00934 | 0.0273 | 0.342 | 0.33 | 0.0549 | 0.636 |
| quasimelita_formosa | 0.00927 | 0.0175 | 0.53 | 0.0294 | 0.332 | 0.646 |
| polygordius_sp | 0.00916 | 0.0207 | 0.443 | 0.359 | 0 | 0.656 |
| cistenides_granulata | 0.00881 | 0.0162 | 0.543 | 0.217 | 0.145 | 0.666 |
| nephtys_caeca | 0.00802 | 0.0146 | 0.55 | 0.226 | 0.0435 | 0.675 |
| aceroides_aceroides_latipes | 0.00741 | 0.0149 | 0.497 | 0.0114 | 0.279 | 0.683 |
| hediste_diversicolor | 0.0073 | 0.0182 | 0.401 | 0.102 | 0.169 | 0.691 |
| ameritella_agilis | 0.00717 | 0.0166 | 0.432 | 0.192 | 0.0591 | 0.698 |
1 mm community
Habitat and metals
| Mean | SD | SE | Median | Min | Max | 95% CI | |
|---|---|---|---|---|---|---|---|
| depth | 21.501 | 17.095 | 1.876 | 18.700 | 1.0 | 66.600 | 3.678 |
| om | 0.718 | 0.699 | 0.077 | 0.476 | 0.2 | 3.872 | 0.150 |
| gravel | 0.068 | 0.152 | 0.017 | 0.000 | 0.0 | 0.809 | 0.033 |
| sand | 0.638 | 0.335 | 0.037 | 0.746 | 0.0 | 1.000 | 0.072 |
| silt | 0.250 | 0.273 | 0.030 | 0.101 | 0.0 | 0.942 | 0.059 |
| clay | 0.044 | 0.108 | 0.012 | 0.000 | 0.0 | 0.497 | 0.023 |
| arsenic | 3.564 | 3.575 | 0.552 | 2.600 | 1.10 | 21.30 | 1.081 |
| cadmium | 0.132 | 0.036 | 0.006 | 0.130 | 0.07 | 0.22 | 0.011 |
| chromium | 51.767 | 22.888 | 3.532 | 45.500 | 17.00 | 111.00 | 6.922 |
| copper | 9.300 | 6.826 | 1.053 | 8.100 | 2.40 | 28.80 | 2.064 |
| iron | 49195.114 | 15793.514 | 2436.992 | 45131.850 | 21938.10 | 86123.70 | 4776.417 |
| manganese | 857.457 | 378.804 | 58.451 | 761.900 | 318.40 | 2098.00 | 114.561 |
| mercury | 0.017 | 0.011 | 0.002 | 0.014 | 0.00 | 0.04 | 0.003 |
| lead | 4.645 | 2.614 | 0.403 | 3.850 | 2.00 | 12.10 | 0.790 |
| zinc | 54.281 | 26.473 | 4.085 | 46.700 | 26.90 | 141.40 | 8.006 |
| Mean | SD | SE | Median | Min | Max | 95% CI | |
|---|---|---|---|---|---|---|---|
| depth | 16.111 | 13.159 | 2.533 | 13.300 | 2.600 | 54.200 | 4.964 |
| om | 0.353 | 0.179 | 0.034 | 0.306 | 0.168 | 0.895 | 0.067 |
| gravel | 0.022 | 0.047 | 0.009 | 0.000 | 0.000 | 0.152 | 0.018 |
| sand | 0.924 | 0.093 | 0.018 | 0.969 | 0.614 | 1.001 | 0.035 |
| silt | 0.047 | 0.063 | 0.012 | 0.021 | 0.000 | 0.227 | 0.024 |
| clay | 0.006 | 0.012 | 0.002 | 0.002 | 0.000 | 0.061 | 0.005 |
| arsenic | 1.833 | 0.896 | 0.517 | 2.30 | 0.800 | 2.400 | 1.014 |
| cadmium | 0.097 | 0.006 | 0.003 | 0.10 | 0.090 | 0.100 | 0.007 |
| chromium | 32.733 | 9.122 | 5.267 | 32.00 | 24.000 | 42.200 | 10.322 |
| copper | 6.367 | 2.401 | 1.386 | 5.40 | 4.600 | 9.100 | 2.717 |
| iron | 33559.100 | 7909.177 | 4566.366 | 29711.60 | 28309.800 | 42655.900 | 8949.912 |
| manganese | 569.767 | 148.562 | 85.772 | 567.60 | 422.300 | 719.400 | 168.110 |
| mercury | 0.011 | 0.005 | 0.003 | 0.01 | 0.007 | 0.017 | 0.006 |
| lead | 2.633 | 0.635 | 0.367 | 3.00 | 1.900 | 3.000 | 0.719 |
| zinc | 39.767 | 5.391 | 3.113 | 39.00 | 34.800 | 45.500 | 6.100 |
| Mean | SD | SE | Median | Min | Max | 95% CI | |
|---|---|---|---|---|---|---|---|
| depth | 32.519 | 19.270 | 2.043 | 29.700 | 1.900 | 77.000 | 4.003 |
| om | 1.769 | 0.967 | 0.102 | 1.529 | 0.288 | 4.415 | 0.201 |
| gravel | 0.017 | 0.098 | 0.010 | 0.000 | 0.000 | 0.765 | 0.020 |
| sand | 0.470 | 0.235 | 0.025 | 0.498 | 0.000 | 0.979 | 0.049 |
| silt | 0.484 | 0.234 | 0.025 | 0.480 | 0.017 | 0.881 | 0.049 |
| clay | 0.029 | 0.143 | 0.015 | 0.000 | 0.000 | 0.979 | 0.030 |
| arsenic | 3.958 | 2.382 | 0.253 | 3.100 | 1.70 | 16.000 | 0.495 |
| cadmium | 0.142 | 0.035 | 0.004 | 0.140 | 0.06 | 0.270 | 0.007 |
| chromium | 58.193 | 15.648 | 1.659 | 58.000 | 31.10 | 106.000 | 3.251 |
| copper | 12.255 | 4.735 | 0.502 | 12.900 | 3.00 | 26.300 | 0.984 |
| iron | 54963.176 | 15905.789 | 1686.010 | 55153.500 | 28355.90 | 151226.400 | 3304.519 |
| manganese | 1174.708 | 587.250 | 62.248 | 1019.800 | 423.10 | 3435.200 | 122.005 |
| mercury | 0.026 | 0.017 | 0.002 | 0.022 | 0.00 | 0.091 | 0.004 |
| lead | 5.590 | 1.860 | 0.197 | 5.500 | 1.70 | 12.200 | 0.386 |
| zinc | 61.607 | 15.872 | 1.682 | 63.600 | 27.60 | 130.000 | 3.297 |
Diversity
| Mean | SD | SE | Median | Min | Max | 95% CI | |
|---|---|---|---|---|---|---|---|
| S | 6.590 | 3.787 | 0.416 | 6.000 | 1 | 17.000 | 0.815 |
| N | 39.590 | 84.647 | 9.291 | 17.000 | 1 | 674.000 | 18.211 |
| H | 1.313 | 0.552 | 0.061 | 1.332 | 0 | 2.555 | 0.119 |
| J | 0.767 | 0.213 | 0.023 | 0.821 | 0 | 1.000 | 0.046 |
| delta | 55.169 | 18.598 | 2.041 | 58.974 | 0 | 87.500 | 4.001 |
| delta_plus | 77.601 | 13.916 | 1.528 | 81.071 | 0 | 87.500 | 2.994 |
| delta_star | 77.267 | 14.604 | 1.603 | 81.250 | 0 | 87.500 | 3.142 |
| Mean | SD | SE | Median | Min | Max | 95% CI | |
|---|---|---|---|---|---|---|---|
| S | 3.037 | 1.675 | 0.322 | 3.000 | 1 | 8.000 | 0.632 |
| N | 18.148 | 22.127 | 4.258 | 9.000 | 2 | 96.000 | 8.346 |
| H | 0.688 | 0.451 | 0.087 | 0.639 | 0 | 1.475 | 0.170 |
| J | 0.606 | 0.338 | 0.065 | 0.715 | 0 | 1.000 | 0.127 |
| delta | 39.144 | 26.038 | 5.011 | 43.750 | 0 | 87.500 | 9.822 |
| delta_plus | 71.099 | 30.464 | 5.863 | 82.589 | 0 | 87.500 | 11.491 |
| delta_star | 72.177 | 30.873 | 5.942 | 86.061 | 0 | 87.500 | 11.645 |
| Mean | SD | SE | Median | Min | Max | 95% CI | |
|---|---|---|---|---|---|---|---|
| S | 10.112 | 3.918 | 0.415 | 10.000 | 3.000 | 19.000 | 0.814 |
| N | 47.483 | 38.162 | 4.045 | 39.000 | 3.000 | 254.000 | 7.928 |
| H | 1.784 | 0.462 | 0.049 | 1.899 | 0.643 | 2.646 | 0.096 |
| J | 0.803 | 0.134 | 0.014 | 0.838 | 0.433 | 1.000 | 0.028 |
| delta | 62.022 | 12.187 | 1.292 | 65.556 | 20.356 | 79.167 | 2.532 |
| delta_plus | 79.668 | 2.591 | 0.275 | 79.722 | 71.250 | 85.000 | 0.538 |
| delta_star | 78.875 | 4.589 | 0.486 | 79.453 | 63.580 | 88.001 | 0.953 |
Here are the graphs plotting specific richness and taxonomic distinctness:
As a measure of \(\beta\) diversity, mean Bray-Curtis dissimilarity is:
- 0.93 within cluster 1
- 0.69 within cluster 2
- 0.75 within cluster 3
Characteristic taxa
## cluster indicator_value probability
## cistenides_granulata 1 0.2935 0.001
## crenella_decussata 1 0.1868 0.002
## phoxocephalus_holbolli 1 0.1651 0.015
## strongylocentrotus_sp 1 0.1267 0.030
## limecola_balthica 1 0.1264 0.011
## hiatella_arctica 1 0.1084 0.011
## pagurus_pubescens 1 0.0843 0.021
## parvicardium_pinnulatum 1 0.0768 0.027
## boreochiton_ruber 1 0.0723 0.032
## caprella_septentrionalis 1 0.0723 0.034
## lepeta_caeca 1 0.0723 0.037
## ophiura_robusta 1 0.0723 0.028
## ampharetidae_spp 1 0.0602 0.025
## echinarachnius_parma 2 0.5561 0.001
## mesodesma_arctatum 2 0.4543 0.001
## nephtys_bucera 2 0.0913 0.018
## eudorellopsis_integra 3 0.6416 0.001
## macoma_calcarea 3 0.6097 0.001
## ennucula_tenuis 3 0.5109 0.001
## bipalponephtys_neotena 3 0.5016 0.001
## goniada_maculata 3 0.4393 0.001
## leucon_leucon_nasicoides 3 0.3708 0.001
## protomedeia_grandimana 3 0.3549 0.001
## pholoe_sp 3 0.3061 0.001
## pontoporeia_femorata 3 0.2665 0.003
## quasimelita_formosa 3 0.2593 0.001
## nephtys_incisa 3 0.2587 0.002
## thyasira_gouldi 3 0.2575 0.001
## maldanidae_spp 3 0.2411 0.001
## polynoidae_spp 3 0.2070 0.006
## oligochaeta 3 0.1605 0.006
## axinopsida_orbiculata 3 0.1492 0.006
## aceroides_aceroides_latipes 3 0.1385 0.002
## chaetodermatida 3 0.1255 0.018
## hediste_diversicolor 3 0.1243 0.024
## protomedeia_fasciata 3 0.1236 0.011
## sipuncula 3 0.1109 0.021
## nuculana_minuta 3 0.1025 0.027
## akanthophoreus_gracilis 3 0.1011 0.020
## praxillella_praetermissa 3 0.0894 0.037
## diastylis_rathkei 3 0.0787 0.034
## eudorella_emarginata 3 0.0674 0.046
##
## Sum of probabilities = 68.843
##
## Sum of Indicator Values = 12.8
##
## Sum of Significant Indicator Values = 9.22
##
## Number of Significant Indicators = 42
##
## Significant Indicator Distribution
##
## 1 2 3
## 13 3 26
| phylum | cl1 | cl2 | cl3 |
|---|---|---|---|
| Arthropoda | 1294 | 28 | 1743 |
| Mollusca | 661 | 199 | 905 |
| Annelida | 598 | 27 | 1499 |
| Echinodermata | 562 | 235 | 31 |
| Nematoda | 145 | 1 | 19 |
| Nemertea | 13 | 0 | 4 |
| Cnidaria | 6 | 0 | 0 |
| Sipuncula | 4 | 0 | 23 |
| Brachiopoda | 2 | 0 | 0 |
| Platyhelminthes | 1 | 0 | 2 |
| average | sd | ratio | ava | avb | cumsum | |
|---|---|---|---|---|---|---|
| echinarachnius_parma | 0.137 | 0.128 | 1.07 | 0.513 | 1.54 | 0.149 |
| mesodesma_arctatum | 0.0969 | 0.124 | 0.779 | 0.0664 | 1.11 | 0.254 |
| cistenides_granulata | 0.0482 | 0.0816 | 0.591 | 0.533 | 0.0257 | 0.306 |
| strongylocentrotus_sp | 0.0311 | 0.0626 | 0.497 | 0.27 | 0.133 | 0.34 |
| phoxocephalus_holbolli | 0.0296 | 0.0597 | 0.495 | 0.341 | 0.0721 | 0.372 |
| nephtys_caeca | 0.027 | 0.0439 | 0.615 | 0.184 | 0.169 | 0.401 |
| nematoda | 0.0202 | 0.0602 | 0.336 | 0.255 | 0.0257 | 0.423 |
| macoma_calcarea | 0.0201 | 0.046 | 0.436 | 0.257 | 0.0721 | 0.445 |
| limecola_balthica | 0.0185 | 0.0479 | 0.387 | 0.178 | 0.0257 | 0.465 |
| protomedeia_grandimana | 0.0163 | 0.0526 | 0.309 | 0.245 | 0 | 0.483 |
| crenella_decussata | 0.0163 | 0.039 | 0.418 | 0.244 | 0 | 0.501 |
| amphipholis_squamata | 0.0157 | 0.051 | 0.308 | 0.125 | 0.0513 | 0.518 |
| scoloplos_armiger | 0.0154 | 0.0505 | 0.306 | 0.143 | 0.0407 | 0.534 |
| ameritella_agilis | 0.0145 | 0.0463 | 0.313 | 0.161 | 0.0257 | 0.55 |
| harmothoe_imbricata | 0.0133 | 0.042 | 0.318 | 0.0815 | 0.0407 | 0.564 |
| orchomenella_minuta | 0.0127 | 0.0394 | 0.323 | 0.0626 | 0.092 | 0.578 |
| mya_arenaria | 0.0123 | 0.0307 | 0.402 | 0.0951 | 0.0513 | 0.592 |
| caprella_septentrionalis | 0.0104 | 0.0398 | 0.261 | 0.217 | 0 | 0.603 |
| ciliatocardium_ciliatum | 0.0102 | 0.0394 | 0.259 | 0.0564 | 0.0596 | 0.614 |
| psammonyx_nobilis | 0.00952 | 0.0412 | 0.231 | 0.0652 | 0.0257 | 0.624 |
| diastylis_sculpta | 0.00939 | 0.0362 | 0.259 | 0.0873 | 0.0257 | 0.635 |
| hiatella_arctica | 0.00873 | 0.0311 | 0.281 | 0.13 | 0 | 0.644 |
| ophelia_limacina | 0.00866 | 0.0265 | 0.327 | 0.0766 | 0.0257 | 0.653 |
| ophiura_robusta | 0.00853 | 0.0347 | 0.246 | 0.19 | 0 | 0.663 |
| nephtys_bucera | 0.0085 | 0.0241 | 0.352 | 0.0167 | 0.077 | 0.672 |
| polynoidae_spp | 0.00813 | 0.0251 | 0.324 | 0.109 | 0.0257 | 0.681 |
| pholoe_sp | 0.00738 | 0.0236 | 0.313 | 0.0528 | 0.0513 | 0.689 |
| nephtys_incisa | 0.00738 | 0.0232 | 0.318 | 0.0633 | 0.0257 | 0.697 |
| average | sd | ratio | ava | avb | cumsum | |
|---|---|---|---|---|---|---|
| eudorellopsis_integra | 0.0613 | 0.0605 | 1.01 | 0.0432 | 1.3 | 0.0647 |
| macoma_calcarea | 0.0613 | 0.0595 | 1.03 | 0.257 | 1.13 | 0.129 |
| protomedeia_grandimana | 0.0415 | 0.0494 | 0.841 | 0.245 | 0.823 | 0.173 |
| bipalponephtys_neotena | 0.0389 | 0.0507 | 0.767 | 0.0444 | 0.842 | 0.214 |
| ennucula_tenuis | 0.0378 | 0.0424 | 0.891 | 0.0766 | 0.769 | 0.254 |
| cistenides_granulata | 0.0283 | 0.0439 | 0.645 | 0.533 | 0.119 | 0.284 |
| pontoporeia_femorata | 0.028 | 0.0494 | 0.566 | 0.0768 | 0.555 | 0.313 |
| goniada_maculata | 0.0268 | 0.0326 | 0.823 | 0.0432 | 0.549 | 0.342 |
| echinarachnius_parma | 0.0265 | 0.0416 | 0.637 | 0.513 | 0.102 | 0.37 |
| maldanidae_spp | 0.024 | 0.0451 | 0.533 | 0.0611 | 0.516 | 0.395 |
| leucon_leucon_nasicoides | 0.0238 | 0.0387 | 0.616 | 0 | 0.527 | 0.42 |
| pholoe_sp | 0.0207 | 0.032 | 0.649 | 0.0528 | 0.42 | 0.442 |
| thyasira_gouldi | 0.0199 | 0.0345 | 0.578 | 0.0383 | 0.421 | 0.463 |
| phoxocephalus_holbolli | 0.0179 | 0.0343 | 0.522 | 0.341 | 0.0849 | 0.482 |
| polynoidae_spp | 0.0175 | 0.0283 | 0.618 | 0.109 | 0.328 | 0.5 |
| nephtys_incisa | 0.0172 | 0.026 | 0.659 | 0.0633 | 0.343 | 0.518 |
| quasimelita_formosa | 0.0167 | 0.0308 | 0.542 | 0.0299 | 0.36 | 0.536 |
| nephtys_caeca | 0.0152 | 0.0302 | 0.504 | 0.184 | 0.124 | 0.552 |
| nematoda | 0.0142 | 0.0379 | 0.374 | 0.255 | 0.0915 | 0.567 |
| axinopsida_orbiculata | 0.0138 | 0.0334 | 0.412 | 0.0334 | 0.257 | 0.582 |
| strongylocentrotus_sp | 0.013 | 0.0336 | 0.387 | 0.27 | 0.00779 | 0.595 |
| oligochaeta | 0.0112 | 0.0294 | 0.382 | 0.0132 | 0.266 | 0.607 |
| thracia_septentrionalis | 0.0111 | 0.0305 | 0.362 | 0.13 | 0.128 | 0.619 |
| crenella_decussata | 0.0105 | 0.025 | 0.419 | 0.244 | 0.00779 | 0.63 |
| ameritella_agilis | 0.00922 | 0.0275 | 0.336 | 0.161 | 0.0357 | 0.64 |
| limecola_balthica | 0.00891 | 0.025 | 0.356 | 0.178 | 0 | 0.649 |
| thyasira_sp | 0.00847 | 0.0307 | 0.276 | 0.0277 | 0.126 | 0.658 |
| diastylis_sculpta | 0.00835 | 0.0263 | 0.318 | 0.0873 | 0.0883 | 0.667 |
| scoloplos_armiger | 0.00828 | 0.0293 | 0.282 | 0.143 | 0.0304 | 0.675 |
| hediste_diversicolor | 0.00814 | 0.0199 | 0.409 | 0.0299 | 0.171 | 0.684 |
| praxillella_praetermissa | 0.0079 | 0.0308 | 0.256 | 0.0167 | 0.128 | 0.692 |
| average | sd | ratio | ava | avb | cumsum | |
|---|---|---|---|---|---|---|
| echinarachnius_parma | 0.0938 | 0.079 | 1.19 | 1.54 | 0.102 | 0.0958 |
| macoma_calcarea | 0.0756 | 0.0711 | 1.06 | 0.0721 | 1.13 | 0.173 |
| eudorellopsis_integra | 0.073 | 0.0701 | 1.04 | 0 | 1.3 | 0.248 |
| mesodesma_arctatum | 0.064 | 0.0819 | 0.781 | 1.11 | 0 | 0.313 |
| bipalponephtys_neotena | 0.0453 | 0.0586 | 0.773 | 0 | 0.842 | 0.359 |
| ennucula_tenuis | 0.0451 | 0.0499 | 0.903 | 0 | 0.769 | 0.405 |
| protomedeia_grandimana | 0.0429 | 0.0521 | 0.823 | 0 | 0.823 | 0.449 |
| goniada_maculata | 0.0308 | 0.0367 | 0.84 | 0.0257 | 0.549 | 0.481 |
| pontoporeia_femorata | 0.0301 | 0.055 | 0.547 | 0 | 0.555 | 0.511 |
| leucon_leucon_nasicoides | 0.028 | 0.0445 | 0.629 | 0 | 0.527 | 0.54 |
| maldanidae_spp | 0.0261 | 0.0526 | 0.497 | 0 | 0.516 | 0.567 |
| pholoe_sp | 0.0241 | 0.0363 | 0.665 | 0.0513 | 0.42 | 0.591 |
| thyasira_gouldi | 0.0221 | 0.0396 | 0.56 | 0 | 0.421 | 0.614 |
| nephtys_incisa | 0.0191 | 0.0297 | 0.644 | 0.0257 | 0.343 | 0.634 |
| quasimelita_formosa | 0.0187 | 0.0354 | 0.529 | 0 | 0.36 | 0.653 |
| polynoidae_spp | 0.0184 | 0.0311 | 0.592 | 0.0257 | 0.328 | 0.672 |
| nephtys_caeca | 0.0169 | 0.0333 | 0.508 | 0.169 | 0.124 | 0.689 |
2. Regressions
2.1. Data manipulation
For the following analyses, independant variables are habitat parameters and heavy metal concentrations, dependant variables are diversity indices. Variables have been standardized by mean and standard-deviation.
2.1.1. Identification of outliers
To identify stations that are not consistent with the others, we used the multivariate Cook’s Distance (CD) on the uncorrelated variables. A significative threshold of 4 times the mean of CD has been established.
0.5 mm community
We identified the following stations as general outliers:
- stations 30, 127, 138, 144, 183, 228, 237 for habitat
- stations 1, 11, 22, 25, 35, 127, 132, 139, 231 for metals
They have been deleted for the following analyses.
1 mm community
We identified the following stations as general outliers:
- stations 72, 82, 107, 129, 144, 202, 249 for habitat
- stations 106, 108, 110, 120, 127, 130, 139, 154, 232 for metals
They have been deleted for the following analyses.
2.1.2. Correlations between predictors
Correlations have been calculated with Spearman’s rank coefficient.
0.5 mm community
According to these results, the following variables are highly correlated (\(|\rho|\) > 0.80) so they have been considered together in the regressions:
- chromium, iron and manganese (iron and manganese deleted)
- copper, lead and zinc (copper and lead deleted)
We decided to exclude silt content, as it tends to drastically increase VIFs due to a marginal correlation with organic matter (\(R^{2}_{adj}\) = 0.21).
| depth | om | gravel | sand | silt | clay | delta | delta_plus | delta_star | |
|---|---|---|---|---|---|---|---|---|---|
| depth | 1 | 0.298 | -0.26 | 0.209 | 0.497 | -0.483 | 0.468 | 0.361 | 0.211 |
| om | 0.298 | 1 | -0.504 | -0.407 | 0.479 | 0.01 | -0.074 | -0.237 | -0.368 |
| gravel | -0.26 | -0.504 | 1 | 0.019 | -0.347 | 0.162 | 0.076 | 0.001 | 0.147 |
| sand | 0.209 | -0.407 | 0.019 | 1 | -0.007 | -0.749 | 0.128 | 0.35 | 0.348 |
| silt | 0.497 | 0.479 | -0.347 | -0.007 | 1 | -0.534 | 0.214 | 0.284 | 0.087 |
| clay | -0.483 | 0.01 | 0.162 | -0.749 | -0.534 | 1 | -0.263 | -0.432 | -0.363 |
| delta | 0.468 | -0.074 | 0.076 | 0.128 | 0.214 | -0.263 | 1 | 0.252 | 0.27 |
| delta_plus | 0.361 | -0.237 | 0.001 | 0.35 | 0.284 | -0.432 | 0.252 | 1 | 0.618 |
| delta_star | 0.211 | -0.368 | 0.147 | 0.348 | 0.087 | -0.363 | 0.27 | 0.618 | 1 |
| arsenic | cadmium | chromium | copper | iron | manganese | mercury | lead | zinc | delta | delta_plus | delta_star | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| arsenic | 1 | 0.732 | 0.631 | 0.713 | 0.405 | 0.62 | 0.711 | 0.865 | 0.808 | -0.137 | -0.147 | -0.329 |
| cadmium | 0.732 | 1 | 0.784 | 0.691 | 0.514 | 0.669 | 0.66 | 0.854 | 0.838 | -0.245 | -0.084 | -0.322 |
| chromium | 0.631 | 0.784 | 1 | 0.738 | 0.8 | 0.891 | 0.467 | 0.75 | 0.792 | -0.333 | -0.27 | -0.361 |
| copper | 0.713 | 0.691 | 0.738 | 1 | 0.571 | 0.738 | 0.612 | 0.843 | 0.928 | -0.283 | -0.286 | -0.529 |
| iron | 0.405 | 0.514 | 0.8 | 0.571 | 1 | 0.83 | 0.187 | 0.458 | 0.571 | -0.269 | -0.142 | -0.266 |
| manganese | 0.62 | 0.669 | 0.891 | 0.738 | 0.83 | 1 | 0.463 | 0.681 | 0.738 | -0.321 | -0.302 | -0.434 |
| mercury | 0.711 | 0.66 | 0.467 | 0.612 | 0.187 | 0.463 | 1 | 0.787 | 0.683 | -0.085 | 0.027 | -0.25 |
| lead | 0.865 | 0.854 | 0.75 | 0.843 | 0.458 | 0.681 | 0.787 | 1 | 0.928 | -0.251 | -0.181 | -0.426 |
| zinc | 0.808 | 0.838 | 0.792 | 0.928 | 0.571 | 0.738 | 0.683 | 0.928 | 1 | -0.271 | -0.195 | -0.458 |
| delta | -0.137 | -0.245 | -0.333 | -0.283 | -0.269 | -0.321 | -0.085 | -0.251 | -0.271 | 1 | 0.312 | 0.352 |
| delta_plus | -0.147 | -0.084 | -0.27 | -0.286 | -0.142 | -0.302 | 0.027 | -0.181 | -0.195 | 0.312 | 1 | 0.575 |
| delta_star | -0.329 | -0.322 | -0.361 | -0.529 | -0.266 | -0.434 | -0.25 | -0.426 | -0.458 | 0.352 | 0.575 | 1 |
1 mm community
According to these results, the following variables are highly correlated (\(|\rho|\) > 0.80) so they have been considered together in the regressions:
- om and silt (silt deleted)
- chromium, iron and manganese (iron and manganese deleted)
- copper, lead and zinc (copper and lead deleted)
| depth | om | gravel | sand | silt | clay | delta | delta_plus | delta_star | |
|---|---|---|---|---|---|---|---|---|---|
| depth | 1 | 0.442 | -0.026 | -0.328 | 0.317 | -0.097 | 0.497 | 0.113 | 0.138 |
| om | 0.442 | 1 | -0.304 | -0.798 | 0.841 | -0.125 | 0.273 | -0.116 | -0.163 |
| gravel | -0.026 | -0.304 | 1 | 0.124 | -0.383 | -0.023 | -0.099 | 0.027 | -0.001 |
| sand | -0.328 | -0.798 | 0.124 | 1 | -0.927 | -0.12 | -0.19 | 0.143 | 0.169 |
| silt | 0.317 | 0.841 | -0.383 | -0.927 | 1 | 0.069 | 0.216 | -0.133 | -0.155 |
| clay | -0.097 | -0.125 | -0.023 | -0.12 | 0.069 | 1 | -0.112 | -0.102 | -0.113 |
| delta | 0.497 | 0.273 | -0.099 | -0.19 | 0.216 | -0.112 | 1 | 0.166 | 0.17 |
| delta_plus | 0.113 | -0.116 | 0.027 | 0.143 | -0.133 | -0.102 | 0.166 | 1 | 0.788 |
| delta_star | 0.138 | -0.163 | -0.001 | 0.169 | -0.155 | -0.113 | 0.17 | 0.788 | 1 |
| arsenic | cadmium | chromium | copper | iron | manganese | mercury | lead | zinc | delta | delta_plus | delta_star | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| arsenic | 1 | 0.743 | 0.79 | 0.809 | 0.636 | 0.707 | 0.702 | 0.892 | 0.88 | -0.053 | 0.016 | -0.123 |
| cadmium | 0.743 | 1 | 0.772 | 0.639 | 0.541 | 0.662 | 0.669 | 0.833 | 0.812 | -0.257 | -0.109 | -0.291 |
| chromium | 0.79 | 0.772 | 1 | 0.858 | 0.823 | 0.902 | 0.667 | 0.837 | 0.892 | -0.156 | -0.009 | -0.224 |
| copper | 0.809 | 0.639 | 0.858 | 1 | 0.77 | 0.792 | 0.708 | 0.857 | 0.946 | -0.092 | 0.014 | -0.164 |
| iron | 0.636 | 0.541 | 0.823 | 0.77 | 1 | 0.869 | 0.412 | 0.595 | 0.753 | -0.099 | 0.097 | -0.086 |
| manganese | 0.707 | 0.662 | 0.902 | 0.792 | 0.869 | 1 | 0.573 | 0.705 | 0.79 | -0.148 | 0.023 | -0.199 |
| mercury | 0.702 | 0.669 | 0.667 | 0.708 | 0.412 | 0.573 | 1 | 0.844 | 0.743 | -0.138 | -0.12 | -0.275 |
| lead | 0.892 | 0.833 | 0.837 | 0.857 | 0.595 | 0.705 | 0.844 | 1 | 0.928 | -0.128 | -0.102 | -0.275 |
| zinc | 0.88 | 0.812 | 0.892 | 0.946 | 0.753 | 0.79 | 0.743 | 0.928 | 1 | -0.137 | -0.004 | -0.194 |
| delta | -0.053 | -0.257 | -0.156 | -0.092 | -0.099 | -0.148 | -0.138 | -0.128 | -0.137 | 1 | 0.231 | 0.318 |
| delta_plus | 0.016 | -0.109 | -0.009 | 0.014 | 0.097 | 0.023 | -0.12 | -0.102 | -0.004 | 0.231 | 1 | 0.703 |
| delta_star | -0.123 | -0.291 | -0.224 | -0.164 | -0.086 | -0.199 | -0.275 | -0.275 | -0.194 | 0.318 | 0.703 | 1 |
2.2. Univariate regressions
We used linear models for the regressions on diversity indices. Outliers and correlated variables were removed from these analyses. Variables have been standardized by mean and standard-deviation (coefficients need to be back-transformed to be used in predictive models).
We identified which variables were selected after an AIC procedure to predict the best the parameters. Results of the variable selection, according to AIC, and details of the regressions, with diagnostics and cross-validation, are summarized below.
0.5 mm community
| Variable (or combination) | S | N | H | J |
|---|---|---|---|---|
| depth | + | - | + | + |
| om/silt | + | + | - | |
| gravel | + | + | + | |
| sand | + | + | - | |
| clay | + | + | + | - |
| Adjusted \(R^{2}\) | 0.33 | 0.5 | 0.27 | 0.16 |
| Variable (or combination) | S | N | H | J |
|---|---|---|---|---|
| arsenic | - | - | ||
| cadmium | - | - | ||
| chromium/iron/manganese | + | - | - | |
| mercury | - | - | ||
| lead/copper/zinc | + | + | ||
| Adjusted \(R^{2}\) | 0.18 | 0.49 | 0.07 | 0.02 |
Richness/habitat
## FULL MODEL
## Adjusted R2 is: 0.33
| Estimate | Std. Error | t value | Pr(>|t|) | ||
|---|---|---|---|---|---|
| (Intercept) | 0.02378 | 0.06373 | 0.3732 | 0.7095 | |
| depth | 0.2425 | 0.07287 | 3.328 | 0.001097 | * * |
| om | 0.2862 | 0.07987 | 3.584 | 0.0004548 | * * * |
| gravel | 0.2016 | 0.09011 | 2.237 | 0.0267 | * |
| sand | 0.2542 | 0.1164 | 2.183 | 0.03054 | * |
| clay | 0.7458 | 0.1126 | 6.623 | 5.636e-10 | * * * |
## RMSE from cross-validation: 0.8090011
| depth | om | gravel | sand | clay | |
|---|---|---|---|---|---|
| VIF | 1.14 | 1.25 | 1.05 | 1.84 | 1.79 |
## REDUCED MODEL
## Adjusted R2 is: 0.33
| Estimate | Std. Error | t value | Pr(>|t|) | ||
|---|---|---|---|---|---|
| (Intercept) | 0.02378 | 0.06373 | 0.3732 | 0.7095 | |
| depth | 0.2425 | 0.07287 | 3.328 | 0.001097 | * * |
| om | 0.2862 | 0.07987 | 3.584 | 0.0004548 | * * * |
| gravel | 0.2016 | 0.09011 | 2.237 | 0.0267 | * |
| sand | 0.2542 | 0.1164 | 2.183 | 0.03054 | * |
| clay | 0.7458 | 0.1126 | 6.623 | 5.636e-10 | * * * |
## RMSE from cross-validation: 0.8090011
| depth | om | gravel | sand | clay | |
|---|---|---|---|---|---|
| VIF | 1.14 | 1.25 | 1.05 | 1.84 | 1.79 |
Density/habitat
## FULL MODEL
## Adjusted R2 is: 0.5
| Estimate | Std. Error | t value | Pr(>|t|) | ||
|---|---|---|---|---|---|
| (Intercept) | 0.01472 | 0.05775 | 0.2548 | 0.7992 | |
| depth | -0.09499 | 0.06604 | -1.438 | 0.1524 | |
| om | 0.5369 | 0.07238 | 7.418 | 7.649e-12 | * * * |
| gravel | 0.1221 | 0.08167 | 1.495 | 0.137 | |
| sand | 0.5185 | 0.1055 | 4.914 | 2.27e-06 | * * * |
| clay | 0.8915 | 0.1021 | 8.736 | 3.96e-15 | * * * |
## RMSE from cross-validation: 0.7850903
| depth | om | gravel | sand | clay | |
|---|---|---|---|---|---|
| VIF | 1.14 | 1.25 | 1.05 | 1.84 | 1.79 |
## REDUCED MODEL
## Adjusted R2 is: 0.5
| Estimate | Std. Error | t value | Pr(>|t|) | ||
|---|---|---|---|---|---|
| (Intercept) | 0.01472 | 0.05775 | 0.2548 | 0.7992 | |
| depth | -0.09499 | 0.06604 | -1.438 | 0.1524 | |
| om | 0.5369 | 0.07238 | 7.418 | 7.649e-12 | * * * |
| gravel | 0.1221 | 0.08167 | 1.495 | 0.137 | |
| sand | 0.5185 | 0.1055 | 4.914 | 2.27e-06 | * * * |
| clay | 0.8915 | 0.1021 | 8.736 | 3.96e-15 | * * * |
## RMSE from cross-validation: 0.7850903
| depth | om | gravel | sand | clay | |
|---|---|---|---|---|---|
| VIF | 1.14 | 1.25 | 1.05 | 1.84 | 1.79 |
Diversity/habitat
## FULL MODEL
## Adjusted R2 is: 0.26
| Estimate | Std. Error | t value | Pr(>|t|) | ||
|---|---|---|---|---|---|
| (Intercept) | 0.05663 | 0.06356 | 0.891 | 0.3743 | |
| depth | 0.5219 | 0.07268 | 7.181 | 2.822e-11 | * * * |
| om | 0.01009 | 0.07966 | 0.1267 | 0.8993 | |
| gravel | 0.156 | 0.08988 | 1.735 | 0.08467 | |
| sand | -0.07361 | 0.1161 | -0.6339 | 0.5271 | |
| clay | 0.2279 | 0.1123 | 2.029 | 0.04422 | * |
## RMSE from cross-validation: 0.8101494
| depth | om | gravel | sand | clay | |
|---|---|---|---|---|---|
| VIF | 1.14 | 1.25 | 1.05 | 1.84 | 1.79 |
## REDUCED MODEL
## Adjusted R2 is: 0.27
| Estimate | Std. Error | t value | Pr(>|t|) | ||
|---|---|---|---|---|---|
| (Intercept) | 0.05587 | 0.06327 | 0.883 | 0.3786 | |
| depth | 0.535 | 0.07073 | 7.565 | 3.221e-12 | * * * |
| gravel | 0.1584 | 0.08587 | 1.844 | 0.06707 | |
| clay | 0.2884 | 0.06988 | 4.127 | 5.989e-05 | * * * |
## RMSE from cross-validation: 0.8019987
| depth | gravel | clay | |
|---|---|---|---|
| VIF | 1.11 | 1 | 1.12 |
Evenness/habitat
## FULL MODEL
## Adjusted R2 is: 0.15
| Estimate | Std. Error | t value | Pr(>|t|) | ||
|---|---|---|---|---|---|
| (Intercept) | 0.05235 | 0.06563 | 0.7977 | 0.4263 | |
| depth | 0.3094 | 0.07505 | 4.122 | 6.142e-05 | * * * |
| om | -0.1443 | 0.08226 | -1.754 | 0.08146 | |
| gravel | -0.004248 | 0.09281 | -0.04577 | 0.9636 | |
| sand | -0.2053 | 0.1199 | -1.712 | 0.08889 | |
| clay | -0.2228 | 0.116 | -1.921 | 0.05654 |
## RMSE from cross-validation: 0.8333639
| depth | om | gravel | sand | clay | |
|---|---|---|---|---|---|
| VIF | 1.14 | 1.25 | 1.05 | 1.84 | 1.79 |
## REDUCED MODEL
## Adjusted R2 is: 0.16
| Estimate | Std. Error | t value | Pr(>|t|) | ||
|---|---|---|---|---|---|
| (Intercept) | 0.05272 | 0.06493 | 0.8119 | 0.4181 | |
| depth | 0.3095 | 0.07478 | 4.138 | 5.741e-05 | * * * |
| om | -0.1432 | 0.07888 | -1.816 | 0.07132 | |
| sand | -0.2041 | 0.1168 | -1.748 | 0.08245 | |
| clay | -0.2218 | 0.1134 | -1.956 | 0.05228 |
## RMSE from cross-validation: 0.8267531
| depth | om | sand | clay | |
|---|---|---|---|---|
| VIF | 1.14 | 1.21 | 1.8 | 1.75 |
Richness/metals
## FULL MODEL
## Adjusted R2 is: 0.17
| Estimate | Std. Error | t value | Pr(>|t|) | ||
|---|---|---|---|---|---|
| (Intercept) | -0.06047 | 0.0758 | -0.7978 | 0.4264 | |
| arsenic | -0.4048 | 0.1342 | -3.017 | 0.003051 | * * |
| cadmium | -0.6834 | 0.1672 | -4.087 | 7.426e-05 | * * * |
| chromium | -0.01251 | 0.138 | -0.09062 | 0.9279 | |
| mercury | -0.4632 | 0.1701 | -2.723 | 0.007325 | * * |
| lead | 1.038 | 0.2052 | 5.06 | 1.333e-06 | * * * |
## RMSE from cross-validation: 0.8958299
| arsenic | cadmium | chromium | mercury | lead | |
|---|---|---|---|---|---|
| VIF | 1.56 | 2.08 | 1.75 | 1.43 | 2.7 |
## REDUCED MODEL
## Adjusted R2 is: 0.18
| Estimate | Std. Error | t value | Pr(>|t|) | ||
|---|---|---|---|---|---|
| (Intercept) | -0.05982 | 0.07518 | -0.7956 | 0.4276 | |
| arsenic | -0.4045 | 0.1337 | -3.026 | 0.002957 | * * |
| cadmium | -0.6892 | 0.154 | -4.474 | 1.6e-05 | * * * |
| mercury | -0.4584 | 0.161 | -2.847 | 0.005086 | * * |
| lead | 1.031 | 0.19 | 5.427 | 2.524e-07 | * * * |
## RMSE from cross-validation: 0.8902463
| arsenic | cadmium | mercury | lead | |
|---|---|---|---|---|
| VIF | 1.56 | 1.92 | 1.36 | 2.51 |
Density/metals
## FULL MODEL
## Adjusted R2 is: 0.49
| Estimate | Std. Error | t value | Pr(>|t|) | ||
|---|---|---|---|---|---|
| (Intercept) | -0.1098 | 0.05881 | -1.867 | 0.06407 | |
| arsenic | -0.5128 | 0.1041 | -4.926 | 2.398e-06 | * * * |
| cadmium | -0.7432 | 0.1297 | -5.729 | 6.212e-08 | * * * |
| chromium | 0.2695 | 0.1071 | 2.517 | 0.01301 | * |
| mercury | -0.7299 | 0.132 | -5.529 | 1.588e-07 | * * * |
| lead | 1.43 | 0.1592 | 8.986 | 1.907e-15 | * * * |
## RMSE from cross-validation: 0.7065136
| arsenic | cadmium | chromium | mercury | lead | |
|---|---|---|---|---|---|
| VIF | 1.56 | 2.08 | 1.75 | 1.43 | 2.7 |
## REDUCED MODEL
## Adjusted R2 is: 0.49
| Estimate | Std. Error | t value | Pr(>|t|) | ||
|---|---|---|---|---|---|
| (Intercept) | -0.1098 | 0.05881 | -1.867 | 0.06407 | |
| arsenic | -0.5128 | 0.1041 | -4.926 | 2.398e-06 | * * * |
| cadmium | -0.7432 | 0.1297 | -5.729 | 6.212e-08 | * * * |
| chromium | 0.2695 | 0.1071 | 2.517 | 0.01301 | * |
| mercury | -0.7299 | 0.132 | -5.529 | 1.588e-07 | * * * |
| lead | 1.43 | 0.1592 | 8.986 | 1.907e-15 | * * * |
## RMSE from cross-validation: 0.7065136
| arsenic | cadmium | chromium | mercury | lead | |
|---|---|---|---|---|---|
| VIF | 1.56 | 2.08 | 1.75 | 1.43 | 2.7 |
Diversity/metals
## FULL MODEL
## Adjusted R2 is: 0.06
| Estimate | Std. Error | t value | Pr(>|t|) | ||
|---|---|---|---|---|---|
| (Intercept) | 0.03115 | 0.07881 | 0.3952 | 0.6933 | |
| arsenic | -0.115 | 0.1395 | -0.8244 | 0.4112 | |
| cadmium | -0.2287 | 0.1738 | -1.316 | 0.1905 | |
| chromium | -0.2563 | 0.1435 | -1.786 | 0.0764 | |
| mercury | 0.02354 | 0.1769 | 0.1331 | 0.8943 | |
| lead | 0.2542 | 0.2133 | 1.192 | 0.2355 |
## RMSE from cross-validation: 0.9303706
| arsenic | cadmium | chromium | mercury | lead | |
|---|---|---|---|---|---|
| VIF | 1.56 | 2.08 | 1.75 | 1.43 | 2.7 |
## REDUCED MODEL
## Adjusted R2 is: 0.07
| Estimate | Std. Error | t value | Pr(>|t|) | ||
|---|---|---|---|---|---|
| (Intercept) | 0.0391 | 0.077 | 0.5078 | 0.6124 | |
| chromium | -0.2812 | 0.08139 | -3.455 | 0.0007288 | * * * |
## RMSE from cross-validation: 0.9157629
| chromium | |
|---|---|
| VIF | 1 |
Evenness/metals
## FULL MODEL
## Adjusted R2 is: 0.03
| Estimate | Std. Error | t value | Pr(>|t|) | ||
|---|---|---|---|---|---|
| (Intercept) | 0.07716 | 0.07843 | 0.9838 | 0.3269 | |
| arsenic | 0.1621 | 0.1388 | 1.167 | 0.2451 | |
| cadmium | 0.2536 | 0.173 | 1.466 | 0.145 | |
| chromium | -0.238 | 0.1428 | -1.666 | 0.09799 | |
| mercury | 0.1657 | 0.176 | 0.9411 | 0.3483 | |
| lead | -0.3184 | 0.2123 | -1.5 | 0.1359 |
## RMSE from cross-validation: 0.9265784
| arsenic | cadmium | chromium | mercury | lead | |
|---|---|---|---|---|---|
| VIF | 1.56 | 2.08 | 1.75 | 1.43 | 2.7 |
## REDUCED MODEL
## Adjusted R2 is: 0.02
| Estimate | Std. Error | t value | Pr(>|t|) | ||
|---|---|---|---|---|---|
| (Intercept) | 0.05581 | 0.07726 | 0.7224 | 0.4713 | |
| chromium | -0.1744 | 0.08166 | -2.136 | 0.03445 | * |
## RMSE from cross-validation: 0.9269077
| chromium | |
|---|---|
| VIF | 1 |
1 mm community
| Variable (or combination) | S | N | H | J |
|---|---|---|---|---|
| depth | + | - | + | + |
| om/silt | ||||
| gravel | - | |||
| sand | - | - | - | |
| clay | - | - | - | |
| Adjusted \(R^{2}\) | 0.25 | 0.03 | 0.34 | 0.1 |
| Variable (or combination) | S | N | H | J |
|---|---|---|---|---|
| arsenic | ||||
| cadmium | - | - | ||
| chromium/iron/manganese | ||||
| mercury | ||||
| lead/copper/zinc | + | + | ||
| Adjusted \(R^{2}\) | 0.08 | 0 | 0.05 | 0 |
Richness/habitat
## FULL MODEL
## Adjusted R2 is: 0.25
| Estimate | Std. Error | t value | Pr(>|t|) | ||
|---|---|---|---|---|---|
| (Intercept) | -0.04634 | 0.06256 | -0.7407 | 0.4598 | |
| depth | 0.2715 | 0.06482 | 4.188 | 4.307e-05 | * * * |
| om | -0.04458 | 0.1117 | -0.3991 | 0.6903 | |
| gravel | -0.1185 | 0.08561 | -1.384 | 0.1679 | |
| sand | -0.4367 | 0.1322 | -3.304 | 0.001141 | * * |
| clay | -0.5032 | 0.1403 | -3.586 | 0.0004272 | * * * |
## RMSE from cross-validation: 0.8934522
| depth | om | gravel | sand | clay | |
|---|---|---|---|---|---|
| VIF | 1.06 | 1.81 | 1.03 | 2.1 | 1.45 |
## REDUCED MODEL
## Adjusted R2 is: 0.25
| Estimate | Std. Error | t value | Pr(>|t|) | ||
|---|---|---|---|---|---|
| (Intercept) | -0.03361 | 0.06184 | -0.5436 | 0.5874 | |
| depth | 0.2678 | 0.06475 | 4.136 | 5.298e-05 | * * * |
| sand | -0.3869 | 0.07612 | -5.083 | 8.825e-07 | * * * |
| clay | -0.4563 | 0.114 | -4.001 | 9.001e-05 | * * * |
## RMSE from cross-validation: 0.8673699
| depth | sand | clay | |
|---|---|---|---|
| VIF | 1.06 | 1.21 | 1.18 |
Density/habitat
## FULL MODEL
## Adjusted R2 is: 0.02
| Estimate | Std. Error | t value | Pr(>|t|) | ||
|---|---|---|---|---|---|
| (Intercept) | -0.0211 | 0.07296 | -0.2892 | 0.7727 | |
| depth | -0.1713 | 0.07559 | -2.266 | 0.02458 | * |
| om | -0.09757 | 0.1303 | -0.749 | 0.4548 | |
| gravel | 0.002914 | 0.09984 | 0.02919 | 0.9767 | |
| sand | -0.29 | 0.1542 | -1.881 | 0.06147 | |
| clay | -0.3748 | 0.1636 | -2.291 | 0.02309 | * |
## RMSE from cross-validation: 1.008745
| depth | om | gravel | sand | clay | |
|---|---|---|---|---|---|
| VIF | 1.06 | 1.81 | 1.03 | 2.1 | 1.45 |
## REDUCED MODEL
## Adjusted R2 is: 0.03
| Estimate | Std. Error | t value | Pr(>|t|) | ||
|---|---|---|---|---|---|
| (Intercept) | -0.01888 | 0.07186 | -0.2627 | 0.7931 | |
| depth | -0.1719 | 0.07525 | -2.285 | 0.02341 | * |
| sand | -0.1969 | 0.08846 | -2.226 | 0.02718 | * |
| clay | -0.3066 | 0.1325 | -2.314 | 0.02174 | * |
## RMSE from cross-validation: 1.002598
| depth | sand | clay | |
|---|---|---|---|
| VIF | 1.06 | 1.21 | 1.18 |
Diversity/habitat
## FULL MODEL
## Adjusted R2 is: 0.34
| Estimate | Std. Error | t value | Pr(>|t|) | ||
|---|---|---|---|---|---|
| (Intercept) | -0.02566 | 0.05866 | -0.4374 | 0.6623 | |
| depth | 0.4303 | 0.06078 | 7.079 | 2.765e-11 | * * * |
| om | 0.06608 | 0.1047 | 0.631 | 0.5288 | |
| gravel | -0.1077 | 0.08027 | -1.341 | 0.1815 | |
| sand | -0.2444 | 0.124 | -1.971 | 0.05013 | |
| clay | -0.2757 | 0.1316 | -2.096 | 0.03742 | * |
## RMSE from cross-validation: 0.8438226
| depth | om | gravel | sand | clay | |
|---|---|---|---|---|---|
| VIF | 1.06 | 1.81 | 1.03 | 2.1 | 1.45 |
## REDUCED MODEL
## Adjusted R2 is: 0.34
| Estimate | Std. Error | t value | Pr(>|t|) | ||
|---|---|---|---|---|---|
| (Intercept) | -0.02847 | 0.0584 | -0.4875 | 0.6265 | |
| depth | 0.4311 | 0.06067 | 7.105 | 2.348e-11 | * * * |
| gravel | -0.119 | 0.0781 | -1.524 | 0.1292 | |
| sand | -0.3082 | 0.07143 | -4.315 | 2.564e-05 | * * * |
| clay | -0.3236 | 0.1073 | -3.017 | 0.002901 | * * |
## RMSE from cross-validation: 0.8399062
| depth | gravel | sand | clay | |
|---|---|---|---|---|
| VIF | 1.06 | 1.01 | 1.21 | 1.18 |
Evenness/habitat
## FULL MODEL
## Adjusted R2 is: 0.08
| Estimate | Std. Error | t value | Pr(>|t|) | ||
|---|---|---|---|---|---|
| (Intercept) | 0.01566 | 0.06839 | 0.2289 | 0.8192 | |
| depth | 0.2928 | 0.07086 | 4.133 | 5.383e-05 | * * * |
| om | 0.02954 | 0.1221 | 0.2419 | 0.8091 | |
| gravel | 0.008159 | 0.09359 | 0.08718 | 0.9306 | |
| sand | -0.04328 | 0.1445 | -0.2995 | 0.7649 | |
| clay | -0.02071 | 0.1534 | -0.135 | 0.8927 |
## RMSE from cross-validation: 0.9552492
| depth | om | gravel | sand | clay | |
|---|---|---|---|---|---|
| VIF | 1.06 | 1.81 | 1.03 | 2.1 | 1.45 |
## REDUCED MODEL
## Adjusted R2 is: 0.1
| Estimate | Std. Error | t value | Pr(>|t|) | ||
|---|---|---|---|---|---|
| (Intercept) | 0.01448 | 0.0664 | 0.2181 | 0.8276 | |
| depth | 0.3126 | 0.06602 | 4.735 | 4.225e-06 | * * * |
## RMSE from cross-validation: 0.9358617
| depth | |
|---|---|
| VIF | 1 |
Richness/metals
## FULL MODEL
## Adjusted R2 is: 0.07
| Estimate | Std. Error | t value | Pr(>|t|) | ||
|---|---|---|---|---|---|
| (Intercept) | 0.06323 | 0.08253 | 0.7661 | 0.4451 | |
| arsenic | -0.1466 | 0.1335 | -1.098 | 0.2742 | |
| cadmium | -0.5481 | 0.1606 | -3.413 | 0.0008755 | * * * |
| chromium | 0.01217 | 0.1638 | 0.07431 | 0.9409 | |
| mercury | -0.001392 | 0.1293 | -0.01077 | 0.9914 | |
| lead | 0.4503 | 0.2727 | 1.651 | 0.1013 |
## RMSE from cross-validation: 0.9298714
| arsenic | cadmium | chromium | mercury | lead | |
|---|---|---|---|---|---|
| VIF | 1.65 | 1.85 | 1.89 | 1.48 | 3.17 |
## REDUCED MODEL
## Adjusted R2 is: 0.08
| Estimate | Std. Error | t value | Pr(>|t|) | ||
|---|---|---|---|---|---|
| (Intercept) | 0.06172 | 0.08196 | 0.7531 | 0.4529 | |
| cadmium | -0.5082 | 0.149 | -3.409 | 0.000881 | * * * |
| lead | 0.3104 | 0.1476 | 2.103 | 0.03751 | * |
## RMSE from cross-validation: 0.9219954
| cadmium | lead | |
|---|---|---|
| VIF | 1.73 | 1.73 |
Density/metals
## FULL MODEL
## Adjusted R2 is: -0.01
| Estimate | Std. Error | t value | Pr(>|t|) | ||
|---|---|---|---|---|---|
| (Intercept) | 0.01452 | 0.09066 | 0.1602 | 0.873 | |
| arsenic | -0.1569 | 0.1467 | -1.07 | 0.287 | |
| cadmium | -0.161 | 0.1764 | -0.9126 | 0.3633 | |
| chromium | -0.2011 | 0.18 | -1.117 | 0.2661 | |
| mercury | -0.1079 | 0.142 | -0.7597 | 0.4489 | |
| lead | 0.4704 | 0.2995 | 1.57 | 0.1189 |
## RMSE from cross-validation: 1.030112
| arsenic | cadmium | chromium | mercury | lead | |
|---|---|---|---|---|---|
| VIF | 1.65 | 1.85 | 1.89 | 1.48 | 3.17 |
## REDUCED MODEL
## Adjusted R2 is: 0
| Estimate | Std. Error | t value | Pr(>|t|) | ||
|---|---|---|---|---|---|
| (Intercept) | 0.01849 | 0.08981 | 0.2058 | 0.8373 |
## RMSE from cross-validation: 1.011527
Quitting from lines 675-677 (C1_analyses_B.Rmd) Erreur dans Qr$qr[p1, p1, drop = FALSE] : indice hors limites De plus : Il y a eu 35 avis (utilisez warnings() pour les visionner)
Diversity/metals
## FULL MODEL
## Adjusted R2 is: 0.04
| Estimate | Std. Error | t value | Pr(>|t|) | ||
|---|---|---|---|---|---|
| (Intercept) | 0.09394 | 0.08016 | 1.172 | 0.2435 | |
| arsenic | -0.1326 | 0.1297 | -1.023 | 0.3086 | |
| cadmium | -0.4559 | 0.156 | -2.923 | 0.004141 | * * |
| chromium | 0.006562 | 0.1591 | 0.04124 | 0.9672 | |
| mercury | 0.03018 | 0.1255 | 0.2404 | 0.8104 | |
| lead | 0.3954 | 0.2648 | 1.493 | 0.1381 |
## RMSE from cross-validation: 0.8995954
| arsenic | cadmium | chromium | mercury | lead | |
|---|---|---|---|---|---|
| VIF | 1.65 | 1.85 | 1.89 | 1.48 | 3.17 |
## REDUCED MODEL
## Adjusted R2 is: 0.05
| Estimate | Std. Error | t value | Pr(>|t|) | ||
|---|---|---|---|---|---|
| (Intercept) | 0.09219 | 0.07962 | 1.158 | 0.2492 | |
| cadmium | -0.4268 | 0.1448 | -2.948 | 0.003831 | * * |
| lead | 0.2923 | 0.1434 | 2.038 | 0.04365 | * |
## RMSE from cross-validation: 0.8942355
| cadmium | lead | |
|---|---|---|
| VIF | 1.73 | 1.73 |
Evenness/metals
## FULL MODEL
## Adjusted R2 is: -0.04
| Estimate | Std. Error | t value | Pr(>|t|) | ||
|---|---|---|---|---|---|
| (Intercept) | 0.06202 | 0.07961 | 0.779 | 0.4375 | |
| arsenic | -0.05693 | 0.1288 | -0.4421 | 0.6592 | |
| cadmium | -0.04309 | 0.1549 | -0.2782 | 0.7813 | |
| chromium | 0.05701 | 0.158 | 0.3607 | 0.7189 | |
| mercury | 0.03799 | 0.1247 | 0.3047 | 0.7611 | |
| lead | -0.004916 | 0.263 | -0.01869 | 0.9851 |
## RMSE from cross-validation: 0.8928066
| arsenic | cadmium | chromium | mercury | lead | |
|---|---|---|---|---|---|
| VIF | 1.65 | 1.85 | 1.89 | 1.48 | 3.17 |
## REDUCED MODEL
## Adjusted R2 is: 0
| Estimate | Std. Error | t value | Pr(>|t|) | ||
|---|---|---|---|---|---|
| (Intercept) | 0.06244 | 0.07799 | 0.8006 | 0.4249 |
## RMSE from cross-validation: 0.873627
Quitting from lines 699-701 (C1_analyses_B.Rmd) Erreur dans Qr\(qr[p1, p1, drop = FALSE] : indice hors limites De plus : Messages d'avis : 1: Dans CVlm(data = lm_out\)model, form.lm = lm_out, m = 5, printit = F) :
As there is >1 explanatory variable, cross-validation predicted values for a fold are not a linear function of corresponding overall predicted values. Lines that are shown for the different folds are approximate
2: Dans CVlm(data = lm_out$model, form.lm = lm_out, m = 5, printit = F) :
As there is >1 explanatory variable, cross-validation predicted values for a fold are not a linear function of corresponding overall predicted values. Lines that are shown for the different folds are approximate
3: Dans CVlm(data = lm_out$model, form.lm = lm_out, m = 5, printit = F) :
As there is >1 explanatory variable, cross-validation predicted values for a fold are not a linear function of corresponding overall predicted values. Lines that are shown for the different folds are approximate
4: Dans CVlm(data = lm_out$model, form.lm = lm_out, m = 5, printit = F) :
As there is >1 explanatory variable, cross-validation predicted values for a fold are not a linear function of corresponding overall predicted values. Lines that are shown for the different folds are approximate
2.3. Multivariate regression
Independant variables are habitat parameters or heavy metal concentrations, dependant variables are species abundances for each community. Variables have been standardized by mean and standard-deviation, and outliers and correlated variables have been excluded. Taxon densities were (log+1) transformed.
This analysis has been done on PRIMER, with a DistLM to identify the variables that explain the most the community variability and with a dbRDA to plot the results.
0.5 mm community
Habitat
Variables selected by the DistLM procedure have a \(R^{2}\) of 0.27.
Metals
Variables selected by the DistLM procedure have a \(R^{2}\) of 0.18.
1 mm community
Habitat
Variables selected by the DistLM procedure have a \(R^{2}\) of 0.14.
Metals
Variables selected by the DistLM procedure have a \(R^{2}\) of 0.07.